Shadow Demons are one of the six tribes of the Demon race.
They possessed bodies that allowed them to phase through physical matter, and also increase their density to bolster their defense. Using their bodies as the ultimate weapon, no other Demon tribe boasted of versatility as much as they did.
They also possessed resistance to physical attacks and could bypass normal defenses by exploiting the smallest gaps. As a result, even stronger opponents ended up losing to them.
Well, at least back in my days.
The war against the Demons had been a harsh one that claimed many lives. We couldn't continue down that path, which was why we settled on a peace treaty.
Of course, things weren't so simple. Humans would never allow the threat of the Demon scourge to persist, and the Demons couldn't ignore the threat humans posed to their race.